Suggestions for hideanswer
The following packages have something in common with the package hideanswer. The packages are ordered in decreasing similarity.
- codesection: Provides an environment that may be conditionally included
 - optional: Facilitate optional printing of parts of a document
 - version: Conditionally include text
 - versions: Optionally omit pieces of text
 - renditions: Multiple versions from the same content
 - comment: Selectively include/exclude portions of text
 - conditext: Define and manage conditional content
 - multiaudience: Several versions of output from the same source
 - phfcc: Convenient inline commenting in collaborative documents
 - tagging: Document configuration with tags
 - xcomment: Allows selected environments to be included/excluded
 - ifthenx: Extra tests for \ifthenelse
 - xifthen: Extended conditional commands
 - graphicscache: Cache includegraphics calls
 - ifallfalse: Compare a string against a set of other strings
 - to-be-determined: Highlight text passages that need further work
 - switch: A constant time/expandable switch/case
 - ifthen: Conditional commands in LaTeX documents
 - luacensor: Securely redact sensitive information using Lua
 - comment-pln: Comment macros for use in Plain TeX
 - kfupm-math-exam: A LaTeX document style to produce homework, quiz and exam papers
 - exam-n: Exam class, focused on collaborative authoring
 - exam: Package for typesetting exam scripts
 - exam-randomizechoices: Randomize mc choices using the exam class
 - comment_io: A Python script to comment and uncomment lines
 - srcredact: A tool for redacting sources
 - anufinalexam: LaTeX document shell for ANU final exam
 - competences: Track skills of classroom checks
 - eqexam: A stand-alone exam package
 - qcm: A LaTeX2ε class for making multiple choice questionnaires
 - moodle: Generating Moodle quizzes via LaTeX